sum of geometric series formula?Watch

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#1
So it's definitely been awhile since I've done geometric series but i need to use it for a bit of uni work!

I have this: a + a/(1+r) + a/[(1+r)^2] + a/[(1+r)^3] + a/[(1+r)^4]

I know how to go about deriving a general formula for an infinite series but what about this finite one? Help is appreciated!
Thanks!
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8 years ago
#2

To prove it, multiply by k and subtract.

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#3
(Original post by SimonM)

To prove it, multiply by k and subtract.

Great! Thanks a lot!
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